Primer composition



Patented Mar. 3, 1931 OFFICE CHARLES H. PRITHAM, F UPPER DARBY,PENNSYLVANIA PRIMER COMPOSITION N 0 Drawing.

Application filed December 1, 1926.

Serial No. 152,053.

(GRANTED UNDER THE ACT OF MARCH 3, 1883, AS AMENDED APRIL 30, 1928; 3700. G. 757) The invention described herein may be manufactured and usedby or for the Government for governmental purposes without the paymentto me of anyroyalty thereon.

The subject of this invention is a primer composition.

The priming compositions heretofore used in this country have containedpotassium chlorate as one of their principal oxidizing ingredients. Theemployment of this salt is highly undesirable owing to the fact thatwhen the primer is tired potassium chloride is formed which is depositedin the bore of the gun and if not carefully removed will cause corrosionand pitting.

The problem has been sucessfully met for many years in foreign countriesby substituting barium nitrate for the potassium chlorate but the use ofsuch improved composition is only possible in certain types of primerssuch as the Berdan primer,' in which the anvil is contained in thecartridge itself providing considerable space in the primer cup andallowing the use of a suflicient quantity of the primer mixture.

Because the barium mixture is more bulky than the potassium mixture itcan not be successfully employed in the type of primer used in smallarms cartridges of American manufacture in which the anvil occupies partof the space in the primer cup.

I have discovered that the barium nitrate primer mixture above referredto may be modified to give successful results in less than normalcharges by incorporating in the mixture a small percentage of highexplosive consisting of nitrated hydrocarbons or aromatics such astrinitrotoluol trinitrobenzene, trinitroaniline, trinitroanisol, pentaeiythritete- 4a tranitrate or the like.

The amount of high explosive incorporated in the primer varies with thenature of the high explosive used but is generally from 4 to 8%.

A typical example of a non-corrosive primer composition which has beensuccessfully used is in part the standard Swiss primer mixture and hasapproximately the following composition:

Per cen: Fulminate of mercury 37 Barium nitrate 32 Antimony sulphide 28Ground glass 3 To which is added high explosive"- 4 to 8 CHARLES H.PRITHAM.

